Research and analysis

Evidence review of e-cigarettes and heated tobacco products 2018: executive summary

Updated 2 March 2018

1. Introduction

In England, adult smoking prevalence in 2016 was 15.5% and, while it has fallen considerably over the last few decades, smoking remains the leading preventable cause of illness and premature death and one of the largest causes of health inequalities.

This report has been commissioned to summarise evidence to underpin policy and regulation of e-cigarettes and vaping devices.

It is the fourth in a series of reports commissioned by Public Health England (PHE) on e-cigarettes. In particular, this report updates the 2015 PHE cigarettes report.

Since the previous report, heated tobacco products, so-called ‘heat-not-burn’ tobacco products, have come onto the market in the UK and the report will provide evidence on this new product type as well as on e-cigarettes.

2. Methods

The methods and sources of data used in the remaining chapters of the report focus on evidence produced since the previous report in 2015.

The evidence falls into 3 main categories: peer-reviewed literature, surveys and other reports and databases sourced by and made available to PHE, King’s College London and other partner organisations since the publication of the 2015 report.

2.1 Peer-reviewed literature

Searches of the published, peer-reviewed literature on e-cigarette published between 1 January 2015 and 18 August 2017.

A separate literature search was conducted for heat-not-burn products. This was not included in the 2015 report so literature was searched from 1 January 2010 to 13 July 2017.

2.2 Survey data

For youth, these included:

• ASH Smoke-free Great Britain – Youth survey
• Wales Schools Health Research Network
• Scottish Schools Adolescent Lifestyle and Substance Use Survey
• Smoking, Drinking and Drug Use Among Young People in England survey
• Youth Tobacco Policy Survey

For adults, these included:

• ASH Smoke-free Great Britain - Adult survey
• Eurobarometer
• International Tobacco Control Policy Evaluation Survey
• Internet cohort Great Britain survey
• Opinions and lifestyle survey
• Smoking Toolkit Study

2.3 Other reports and databases

Data from NHS Digital (derived from local authorities) were assessed for Stop Smoking Service information.

Publicly available data from the National Poison Information Service were used for information on poisonings.

UK Fire and Rescue Incident Recording System (as reported by the Home Office) data were used for information on fires due to e-cigarettes.

Freedom of information (FOI) requests were also sent to the UK regional fire and rescue services for information on fires caused by e-cigarettes and mobile phones.

A freedom of information request was sent to burns units, but for many, the cost of accessing the data would have been excessive. No data were included in this report.

The Medicines and Healthcare products Regulatory Agency (MHRA) provided us with details for spontaneous suspected adverse reaction reports for e-cigarettes along with details of suspected adverse drug reactions for nicotine replacement therapy products.

The ECig Intelligence Global Database was used to explore average price of various categories of e-cigarette.

3. Policy

3.1 Key findings

As with tobacco products, in most parts of the UK, there is a minimum age of sale of 18 for e-cigarettes and e-cigarettes cannot be purchased on behalf of someone under the age of 18.

The revised European Union Tobacco Products Directive is now fully operational in England, transposed into UK law through the UK Tobacco and Related Products Regulations 2016, and covers e-cigarettes and nicotine-containing e-liquids that do not have a medicinal licence. These regulations include a notification process to the MHRA, minimum standards for safety and quality of e-cigarette products, standards for information provision (including a nicotine health warning) and advertising restrictions and updated standards. The Advertising Standards Authority has carried out a consultation on health claims; the results are awaited. A system to report side effects and safety concerns related to e-cigarettes has been implemented.

Over 32,000 e-cigarette and nicotine containing e-liquid products have been notified which suggests a level of compliance with the regulations, and that the notification process is not too onerous.

There are some signs that ways are being found to avoid the law, for example particularly on size of bottles, but evidence is limited.

Alongside products regulated in line with the EU Tobacco Products Directive, manufacturers can also apply for medicinal licensing from the MHRA. However, no licensed e-cigarette has yet been marketed.

Other e-cigarette related developments include consensus statements from a number of organisations and guidance on the use of e-cigarettes in public places and on their use in research.

Non-nicotine e-cigarettes are governed by general product safety regulations (unlike combustible tobacco products).

There is a separate notification process for heated tobacco products (to PHE) and results from a consultation on the tax treatment of these products are forthcoming. At the time of writing, 2 products had been notified.

A new Tobacco Control Plan for England was published in July 2017.

3.2 Implications

Research

There is a need for continued research on the impact of regulations on smoking rates and patterns, use of e-cigarettes by adults and young people, product design and quality, and adverse effects of e-cigarettes.

Research should specifically assess the impact of the EU Tobacco Products Directive on production (with a specific focus on independent manufacturers who were the first to enter this field), innovation of products, and e-cigarette users and smokers.

Policy

Regulations need to balance the risks of e-cigarettes with their potential benefits – and achieve key aims of reducing smoking and continuing to avoid uptake of e-cigarettes by non-smokers. This requires keeping them under regular review and evaluating their impact.

Regulations for heated tobacco products should be made as least a stringent as for e-cigarettes.

It remains a viable and important goal to facilitate regulation of some e-cigarettes as medicines via the MHRA. A review is needed of how to achieve this, possibly including more focus on post marketing surveillance and the provision of licences for short-term rather than extended use.

Restrictions on communicating relative risks of e-cigarettes in comparison with combustible tobacco should be reconsidered. In any future review of the EU Tobacco Products Directive, consideration should be given to the wording of the health warning on nicotine per se given public misperceptions of its harmfulness.

There appears to be no evidence justifying an urgent change regarding non-nicotine e-cigarettes or e-liquids which are currently outwith the scope of the EU Tobacco Products Directive.

4. Nicotine

4.1 Key findings

The addictiveness of nicotine depends on the delivery system.

It is possible that the addictiveness of tobacco cigarettes may be enhanced by compounds in the smoke other than nicotine.

As e-cigarettes have evolved, their nicotine delivery has improved. This could mean that their addiction potential has increased, but this may also make them more attractive to smokers as a replacement for smoking. It is not yet clear how addictive e-cigarettes are, or could be, relative to tobacco cigarettes.

While nicotine has effects on physiological systems that could theoretically lead to health harms, at systemic concentrations experienced by smokers and e-cigarette users, long-term use of nicotine by ‘snus’ (a low nitrosamine form of smokeless tobacco) users has not been found to increase the risk of serious health problems in adults, and use of nicotine replacement therapy by pregnant smokers has not been found to increase risk to the foetus.

Adolescent nicotine use (separate from smoking) needs more research.

The long-term impact of nicotine from e-cigarettes on lung tissue is not yet known and may be different from its impact systemically.

4.2 Implications

Research

More research on nicotine in comparison to tobacco cigarette smoking is needed, and the popularity of e-cigarettes enables such research, albeit in the context of the other components in e-cigarette and e-cigarette aerosol.

Further research is needed on the similarities and differences in addictiveness of e-cigarettes and tobacco cigarettes and the potential harms associated with inhaled nicotine.

Policy and practice

Widespread misperceptions about the relative risks of nicotine and tobacco (see Chapter 10) need to be addressed and corrected.

Clear messages, based on current evidence about nicotine, its relationship with harms, and its addictiveness, compared with smoking, are necessary and could have a marked impact on public health.

Policies on tobacco and e-cigarettes should have at their core the recognition that nicotine use per se presents minimal risk of serious harm to physical health and that its addictiveness depends on how it is administered.

5. Use of e-cigarettes among young people

5.1 Key findings

E-cigarettes cannot be legally sold to young people under the age of 18 in most parts of the UK. Purchasing does occur including from sources rarely used for tobacco, such as online suppliers.

Despite some experimentation with these devices among never smokers, e-cigarettes are attracting very few young people who have never smoked into regular use.

E-cigarettes do not appear to be undermining the long-term decline in cigarette smoking in the UK among young people.

Never smokers in the UK who try e-cigarettes are more likely to have tried smoking subsequently than those who have not tried e-cigarettes. A causal link has not been established and neither has progression to regular smoking. The ‘common liability’ hypothesis seems a plausible explanation for the relationship between e-cigarettes and smoking implementation.

5.2 Implications

Trends in e-cigarette use and smoking among youth should continue to be monitored using standardised definitions of use. This should include the use of nicotine in e-cigarettes and checks on the understanding of survey questions.

Patterns of e-cigarette purchasing by young people should be closely monitored, particularly internet sales. Age of sale regulations are in place for e-cigarettes and cigarettes and should be strongly enforced.

Research is needed on trajectories of use - not just from e-cigarette experimentation to smoking, but also from smoking to e-cigarette use among young people.

6. Use of e-cigarettes in adults

6.1 Key findings

Prevalence

In Great Britain, prevalence of e-cigarette use in adults has plateaued at approximately 6% of the adult population.

E-cigarette use among never smokers in Great Britain remains very rare at less than 1%, similar to the level of use of nicotine replacement therapy. Among never smokers who have ever used e-cigarettes, a minority have used nicotine-containing liquids and the vast majority not progressed to regular use.

Prevalence of e-cigarette use and trial among smokers has plateaued while use and trial among ex-smokers continue to increase.

Socio-economic differences in e-cigarette use by smokers and recent ex-smokers have become smaller with no clear gradient in prevalence by occupational grade.

Prevalence of dual use (use and smoking) is similar for e-cigarette users and users of nicotine replacement therapy.

Characteristics of use

Most e-cigarette trial does not become regular use.

Most current e-cigarette users use daily and have used e-cigarettes for more than 6 months.

Models with refillable tanks for liquids are the most widely used type.

Since May 2017, nicotine concentration in liquids has been limited to a maximum of 20mg/mL. In March 2017, around 6% of e-cigarette users reported using higher nicotine concentrations; substantial proportions had difficulties reporting these figures so more may have been affected by the limit.

The most popular groups of flavours among current e-cigarette users are fruit (29%), tobacco (27%) and menthol or mint (25%).

Specialist vape shops (physical premises rather than online) are the most popular place of purchase (>40%).

The most common reason for e-cigarette use continues to be in order to stop smoking, and smokers who use e-cigarettes on average have higher motivation to stop smoking than other smokers.

International

Data can be outdated by the time of publication.

Prevalence of current use in GB is at the higher end for countries in the EU where the average is 2% for current e-cigarette use. Prevalence estimates for current e-cigarette use in the US are around 4% to 6%, which is similar to Great Britain.

Across international surveys, a consistently low prevalence (<1%) of e-cigarette use has been reported among never-smokers; one exception is one Spanish survey at 1.2%.

Prevalence figures found for smokers and ex-smokers vary more widely across surveys in different countries (4% to 22% among smokers and 0.1% to 5% among ex-smokers).

6.2 Implications

Research

As recommended in the 2015 PHE report, trends in e-cigarette use among adults should continue to be monitored using standardised definitions of use. Measures should include frequency and type of device used including different types of tank models.

E-cigarette use among ex-smokers needs monitoring and further evidence to understand when and why they take up e-cigarette use and whether this is associated with an increase or decrease of relapse to smoking.

More research is needed into different patterns of e-cigarette use while smoking and their effect on subsequent smoking behaviour to understand how best to move dual users to stop smoking.

More research is needed on the impact of e-cigarettes on health and economic inequalities associated with smoking; in particular on use of e-cigarettes in disadvantaged groups with high smoking prevalence and smoking-related morbidity and mortality, such as those with mental health problems or offenders. Data that have been gathered from the Adult Psychiatric Morbidity Survey should be released for analysis.

Policy

As recommended in 2015 and as per existing NICE guidance, all smokers should be supported to stop smoking completely, including ‘dual users’ who smoke and use e-cigarettes.

Access to e-cigarettes should be improved for smokers in disadvantaged groups.

7. The effect of e-cigarette use on smoking cessation and reduction

7.1 Key findings

In the first half of 2017, quit success rates in England were at their highest rates so far observed and for the first time, parity across different socio-economic groups was observed. It is plausible that e-cigarettes have contributed to this.

Recent estimates of additional quitters resulting annually from the availability of e-cigarettes, using the same dataset but 2 different methods, resulted in similar figures within the range of 16,000 to 22,000. Varying the assumptions, and updating these estimates for 2016, resulted in an upper bound estimate of around 57,000 additional quitters annually resulting from e-cigarettes (lower bound around 22,000). While caution is needed with these figures, the evidence suggests that e-cigarettes have contributed tens of thousands of additional quitters in England.

E-cigarette use, alone or in combination with licensed medication and behavioural support from a Stop Smoking Service, appear to be helpful in the short term. However, fewer smokers use an e-cigarette as part of a quit attempt with a Stop Smoking Service compared with licensed medication.

We identified 14 systematic reviews of e-cigarettes for smoking cessation and reduction published since our last report, 7 of which included a meta-analysis. The authors of the systematic reviews arrived at the same conclusion that further randomised controlled trials of e-cigarettes are needed. However, the reviews that included a meta-analysis produced different results: 2 found a positive effect on cessation for e-cigarette use, 4 found an inconclusive effect for cessation and one found a negative effect.

7.2 Implications

Research

An important focus of future research is longer-term relapse trajectories of people who use e-cigarettes for quitting compared with other stop smoking treatments and also assess whether the uptake of e-cigarettes after quitting can prevent relapse back to smoking.

Funders should consider that although randomised controlled trials (RCTs) may yield higher internal validity this is at the cost of lower generalisability. Future robust observational studies and RCTs should consider allowing for user experimentation (for example, trial and error of different types of e-cigarette products), as well as the inclusion of study outcomes that are relevant and meaningful for e-cigarette users.

Funders should commission research about the effect of e-cigarettes on smoking cessation in vulnerable populations (for example, people who smoke who have a mental illness, substance misuse disorder, homeless or prison populations).

Policy and practice

Stop smoking practitioners and health professionals should provide behavioural support to smokers who want to use an e-cigarette to help them quit smoking.

Stop smoking service practitioners and health professionals supporting smokers to quit should receive education and training in use of e-cigarettes in quit attempts.

Local authorities should continue to fund and provide Stop Smoking Services in accordance with the evidence base.

8. Poisonings, fires and explosions

8.1 Key findings

Poisonings

There are recorded cases of poisoning from e-liquid in the UK. These have predominantly involved accidental ingestion with fewer incidences of other routes (for example, ocular or dermal) of exposure.

Intentional poisoning using e-liquids has been reported in self-harm and suicide attempts.

Toxic effects from e-cigarette poisoning are usually short in duration and of minimal severity. Severe cases and fatalities, while very rare, have been recorded.

E-cigarette poisonings reported to medical centres most commonly occur in children under 5 years old. Toxic effects for this age group are usually short in duration and non-severe. Fatalities, while very rare, have also been recorded in this age group.

Incidents of poisoning in children are often preventable and have involved liquids stored non-securely, in unmarked containers or in containers without safety caps.

Fires

E-cigarette fires are recorded at the discretion of individual fire and rescue services in the UK. Information provided to us through a Freedom of Information request suggest that, where recorded, they occur in low numbers and are vastly outweighed by fires caused by smokers’ materials. There were no fatalities from fires caused by e-cigarettes in the reporting period.

E-cigarettes or their batteries are recorded as the cause of fires by UK fire and rescue services. The root cause of e-cigarette fires is likely to be through a malfunctioning lithium-ion battery.

Explosions

Exploding e-cigarettes can cause severe burns and injuries that require intensive and prolonged medical treatment especially when they explode in users’ hands, pockets or mouths.

Incidents are very rare. The cause is uncertain but appears to be related to malfunctioning lithium-ion batteries.

8.2 Implications

Research

Research is required on the prevalence of e-liquid poisoning, fires and explosions caused by e-cigarettes in England. This will require some synthesis of existing datasets.

Research on presence and effectiveness of safety features and instructions should be part of a future review of the EU Tobacco Products Directive.

Policy and practice

Monitoring of fires caused by e-cigarettes should be recorded by fire and rescue services in a mandatory way (similar to cooking appliances, smokers’ materials and other electrical appliances) and should not continue to rely on free text entry.

E-cigarettes can trigger fire or smoke detectors and therefore consumers should be advised to move away from detectors when using them.

It is too early to assess the impact of the EU Tobacco Products Directive in reducing poisonings, fires or explosions, or whether further regulations are needed. Therefore, continued monitoring is required to assess effectiveness of EU Tobacco Product Directive regulations (such as childproof containers), in reducing accidental ingestion of e-liquid.

Regulations should require that labelling on e-liquid bottles advises customers to store products away from similar looking medicines such as eye drops, ear drops and children’s medicine.

Regulations should require that labelling reinforces advice on the safe storage and transportation of batteries used by e-cigarettes. For example, advice should be given that e-cigarettes should not be carried in pockets with coins, keys or other metallic objects, and that the correct charger should always be used.

9. Health risks of e-cigarettes

9.1 Key findings

One assessment of the published data on emissions from cigarettes and e-cigarettes calculated the lifetime cancer risks. It concluded that the cancer potencies of e-cigarettes were largely under 0.5% of the risk of smoking.

Comparative risks of cardiovascular disease and lung disease have not been quantified but are likely to be also substantially below the risks of smoking. Among e-cigarette users, 2 studies of biomarker data for acrolein, a potent respiratory irritant, found levels consistent with non-smoking levels.

There have been some studies with adolescents suggesting respiratory symptoms among e-cigarette experimenters. However, small scale or uncontrolled switching studies from smoking to vaping have demonstrated some respiratory improvements.

E-cigarettes can release aldehydes if e-liquids are overheated, but the overheating generates an aversive taste.

To date, there is no clear evidence that specific flavourings pose health risks but there are suggestions that inhalation of some could be a source of preventable risks.

To date, the levels of metals identified in e-cigarette aerosol do not give rise to any significant safety concerns, but metal emissions, however small, are unnecessary.

Biomarkers of exposure assessed to date are consistent with significant reductions in harmful constituents and for a few biomarkers assessed in this chapter, similar levels to smokers abstaining from smoking or non-smokers were observed.

One study showed no reductions across a range of biomarkers for dual users (either for nicotine replacement therapy or e-cigarette dual users).

To date, there have been no identified health risks of passive vaping to bystanders.

Reporting of some academic studies has been misleading.

9.2 Implications

Research

More research is needed with human users about biomarkers of exposure, risk and harm and health effects over time.

More research with biomarkers across the range of different combinations of dual use is needed.

Adverse effects of passive vaping should be monitored.

Policy

Policy makers and regulators should ensure that e-cigarettes are manufactured in a way that minimizes harm. An advantage of e-cigarettes is that particular constituents can be removed or minimised in a way that is not feasible with tobacco cigarettes.

Regulations should therefore be flexible to ensure any emerging evidence of constituent harmfulness can be acted upon, such that products are modified to remove any components shown to pose avoidable risks.

Consumers and health professionals should be encouraged to use the Yellow Card Scheme for reporting adverse reactions to e-cigarette use.

Vaping poses only a small fraction of the risks of smoking and switching completely from smoking to vaping conveys substantial health benefits over continued smoking. Based on current knowledge, stating that vaping is at least 95% less harmful than smoking remains a good way to communicate the large difference in relative risk unambiguously so that more smokers are encouraged to make the switch from smoking to vaping. It should be noted that this does not mean e-cigarettes are safe.

The lack of difference in biomarkers between dual users and smokers found so far underlines the need to encourage and support dual users to stop smoking altogether.

10. Perceptions of relative harms of nicotine, e-cigarettes and smoking

10.1 Key findings

Perceived relative harm of e-cigarettes compared with cigarettes has continued to increase; less than half of adults in Great Britain think e-cigarettes are less harmful than smoking.

Nicotine replacement therapy is subject to similar misperceptions and only just over half of adults in Great Britain think that nicotine replacement therapy is any less harmful than smoking.

Adult smokers are poorly informed about relative risks of different products:

• only half of smokers believe that e-cigarettes are less harmful than smoking and this decreases to one third among smokers who have never tried e-cigarettes
• in contrast to evidence to date, it appears that a majority of smokers and ex-smokers does not think that complete replacement of cigarettes with e-cigarettes would lead to major health benefits
• only half of all adult smokers believe that nicotine replacement therapy is any less harmful than smoking

As the common factor for cigarettes, nicotine replacement therapy and (most) e-cigarettes is nicotine, these misperceptions may be linked to the perception of nicotine:

• when adults in Great Britain are asked what proportion of the health harms of smoking is due to nicotine, the accurate response (most health harms are not caused by nicotine) is the least common response consistently chosen by 8 to 9% and smokers’ knowledge around nicotine is similarly poor
• 4 in 10 smokers and ex-smokers incorrectly think nicotine in cigarettes is the cause of most of the smoking-related cancer
• misperceptions around nicotine and cancer are greater in more disadvantaged groups

It is unclear to what extent the perception of addictiveness underpins the perception of harm.

Among youth in Great Britain, perceived harm of e-cigarettes relative to cigarettes has also increased over time and nicotine knowledge is similarly poor (7% correctly responded that none or a small portion of the harms of smoking is due to nicotine).

Where available, international data show similar misperceptions around nicotine and relative harmfulness of e-cigarettes and smoking as in England. International data also support the trends of increased harm perception of e-cigarettes with the exception of one survey in youth in the US.

10.2 Implications

Research

Future research should aim to assess causes and effects of misperceptions of the relative harmfulness of e-cigarettes and nicotine replacement therapy compared with cigarettes, including to what extent the perception of addictiveness contributes to these misperceptions.

Policy

Misperceptions of nicotine and different nicotine-containing products need to be addressed. These have deteriorated further since the PHE report in 2015 which called for clear and accurate information on relative harms.

Misperceptions of the relative harms of nicotine replacement therapy and e-cigarettes compared with cigarettes need to be addressed, particularly among smokers who would benefit from switching to nicotine replacement therapy or e-cigarettes.

Knowledge about the role of nicotine in the development of cancers and other diseases caused by smoking needs improvement.

11. Pricing

11.1 Key findings

Price varies considerably between products, and there appear to be differences between online and bricks and mortar shop prices, with closed system products tending to be cheaper online, and open system kits cheaper in bricks and mortar shops.

Generally, average maximum and minimum prices seem to have remained relatively stable from August 2015 to July 2017 for all product categories.

There appear to have been no major and consistent changes in price over the first year since implementation of the EU Tobacco Products Directive.

11.2 Implications

Current available data provide minimum, maximum and average prices, but do not provide detail on nicotine levels, brands and flavours that would be helpful to our understanding of market developments.

Currently e-cigarette products are available in a wide range of prices and therefore affordable to various types of e-cigarette users. Any changes in pricing need to ensure that e-cigarettes are affordable to smokers to avoid discouraging smokers from switching away from smoked tobacco which would be counter-productive in public health terms. There should therefore be a competitive advantage for the prices of e-cigarettes compared to combustible tobacco products.

12. Heated tobacco products

12.1 Key findings

In mid 2017, heated tobacco products were commercially available in 27 countries and further country launches were planned. 3 tobacco manufacturers were promoting heated tobacco products: ‘IQOS’ was promoted by Philip Morris International, ‘glo’ by British American Tobacco, and ‘Ploom TECH’ by Japan Tobacco International.

Out of 20 studies that were included in this review, 12 were funded by manufacturing companies so there is a lack of independent research.

There is a variety of heated tobacco products, including some that deliver via both vapour and combustion.

Most studies published at the time of the search for this review evaluated IQOS, none evaluated glo or Ploom TECH. An updated version of the review including later publications is in preparation to be published separately.

In Great Britain, in 2017, awareness and ever use of heated tobacco products were very rare.

Nicotine in mainstream aerosol from heated tobacco products reached 70% to 84% of the nicotine detected in smoke from reference cigarettes.

The tested heated tobacco products delivered more nicotine in aerosol than a cigalike e-cigarette and less nicotine than a tank style e-cigarette.

Pharmacokinetics and delivery of nicotine after single use of a heated tobacco product were generally comparable with smoking a cigarette. However, studies that compared ad libitum use of heated tobacco products with smoking cigarettes consistently reported lower nicotine levels in heated tobacco product users compared with smokers.

Probably to compensate, smokers who were switched to using heated tobacco products adjusted their puffing behaviour.

Heated tobacco product use reduced urges to smoke, but smokers consistently reported heated tobacco product use to be less rewarding compared with smoking a cigarette.

Compared with cigarette smoke, heated tobacco products are likely to expose users and bystanders to lower levels of particulate matter and harmful and potentially harmful compounds. The extent of the reduction found varies between studies.

The limited evidence on environmental emissions from use of heated tobacco products suggests that harmful exposure from heated tobacco products is higher than from e-cigarettes, but further evidence is needed to be able to compare products.

Japan, where e-cigarettes are not available, has the most diverse heated tobacco product market with 3 tobacco manufacturers participating. Past 30 day use for the most frequently used product increased from 0.3% in 2015 to 3.7% in 2017, suggesting rapid penetration of heated tobacco products.

12.2 Implications

Research

There is a need for more research that is independent of commercial interests.

Different types of heated tobacco products will have different characteristics and effects, presenting a challenge for research.

Research is needed on relative risks of heated tobacco products to users and those around them compared with cigarettes and e-cigarettes.

Evidence is needed on appeal of heated tobacco products to smokers and non-smokers, particularly among youth.

Effects on smoking need to be researched, this includes whether they replace or complement cigarettes. Due to co-branding of some products with cigarettes and the more similar sensory profile, findings may be different than for e-cigarettes.

Future studies, whether funded by manufacturers or independently, should ensure conduct of studies in line with established guidelines such as definitions of abstinence from smoking, using intention-to-treat analysis and registering trial protocols prior to the start of participant recruitment.

The appropriateness of different methods for measuring emissions and their translation from cigarettes to heated tobacco products should be evaluated to be able to recommend a gold standard.

Prevalence and market share should be monitored, particularly in markets targeted by manufacturers:

• in line with recommendations for e-cigarette use, measures should go beyond lifetime use or past 30 day use to assess current use, uptake and use should be assessed by smoking status.
• monitoring should include transitions between smoking, e-cigarette use and heated tobacco product use.

Policy

The available evidence suggests that heated tobacco products may be considerably less harmful than tobacco cigarettes and more harmful than e-cigarettes.

With a diverse and mature e-cigarette market in the UK, it is currently not clear whether heated tobacco products provide any advantage as an additional potential harm reduction product.

Depending on emerging evidence on their relative risk compared to combustible tobacco and e-cigarettes, regulatory levers such as taxation and accessibility restrictions should be applied to favour the least harmful options alongside continued efforts to encourage and support complete cessation of tobacco use.

13. Authors and citation

13.1 Suggested citation

McNeill A, Brose LS, Calder R, Bauld L & Robson D (2018). Evidence review of e-cigarettes and heated tobacco products 2018. A report commissioned by Public Health England. London: Public Health England.

13.2 Authors

Ann McNeill ^{[footnote 1] [footnote 2]} Leonie S Brose ^{[footnote 1] [footnote 2]} Robert Calder ^{[footnote 1]} Linda Bauld ^{[footnote 2] [footnote 3] [footnote 4]} Debbie Robson ^{[footnote 1] [footnote 2]}

Additional contributors to individual chapters

Ilze Bogdanovica (chapter 11) ^{[footnote 2] [footnote 5]}; John Britton (chapter 11) ^{[footnote 2] [footnote 5]}; Jamie Brown (chapter 7) ^{[footnote 2] [footnote 6]}; Peter Hajek (chapters 4,9) ^{[footnote 2] [footnote 7]}; Hyun Seok Lee (chapter 12) ^{[footnote 1]}; Magdalena Opazo Breton (chapter 11) ^{[footnote 2] [footnote 5]}; Lion Shahab (chapters 7,9) ^{[footnote 2] [footnote 6]}; Erikas Simonavicius (chapter 12) ^{[footnote 1]}; Robert West (chapter 7) ^{[footnote 2] [footnote 6]}.

1. King’s College London ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶

2. UK Centre for Tobacco & Alcohol Studies ↩ ↩² ↩³ ↩⁴ ↩⁵ ↩⁶ ↩⁷ ↩⁸ ↩⁹ ↩¹⁰ ↩¹¹

3. University of Stirling ↩

4. Cancer Research UK ↩

5. University of Nottingham ↩ ↩² ↩³

6. University College London ↩ ↩² ↩³

7. Queen Mary, University of London ↩